It has been found out that the probability that a child is a male in family is 0.4. In a family of 6 children, what is the probability that; i. exactly 5 are boys ? ii. at least 4 are boys ? iii. all boys

Answer 1

prob(male) = .4
prob(female) = .6

prob(5 of 6 are male)
= C(6,5) (.4)^5 (.6) = ...

prob(at least 4 of the 6 are boys)
= prob(4 boys) + prob(5 boys) + prob(6 boy s)
= C(6,4) (.4)^4 (.6)^2 + C(6,5) (.4)^5 (.6) + .4^6
= ---

all boys = .4^6